# -*- coding: UTF-8 -*-
from typing import List
from leetcode_helper import TestcaseHelper, SolutionBase


class Solution(SolutionBase):
    # 解题的方法，命名和Leetcode的保持一致即可
    def permutation(self, s: str) -> List[str]:
        def backtrack(arr, used: List[bool], track: List[str]):
            if len(track) == len(arr):
                nonlocal result
                result.append(''.join(track))
                return

            for index, item in enumerate(arr):
                if used[index]:
                    continue
                if index > 0 and arr[index] == arr[index - 1] and not used[index - 1]:
                    continue

                used[index] = True
                track.append(item)

                backtrack(arr, used, track)

                used[index] = False
                track.pop()

        str_arr = list(s)
        str_arr.sort()
        used_arr = [False] * len(str_arr)
        result = []
        backtrack(str_arr, used_arr, [])

        return result


if __name__ == '__main__':
    solution = Solution()

    # 按照leetcode的题目说明，将基本的test case填入
    # 每条case的最后一个元素是正确的结果，即期待的结果
    # 使用元组来保存输入的数据，期待的结果
    testcases = [
        ("abc", ["abc", "acb", "bac", "bca", "cab", "cba"]),
        ("aab", ['aab', 'aba', 'baa'])
    ]

    for case_item in testcases:
        # 获取测试用的case和期待的执行结果
        input1 = case_item[0]
        expect = case_item[len(case_item) - 1]

        exec_result = solution.permutation(input1)

        # 判断执行结果，输出提示信息
        check_result = solution.check_result(expect, exec_result)
        TestcaseHelper.print_case(check_result, case_item, exec_result)

